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https://issues.apache.org/jira/browse/HIVE-15530?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Yibing Shi updated HIVE-15530:
------------------------------
Description:
Currently when a table is altered, if any of below conditions is true, HMS
would try to update column statistics for the table:
# database name is changed
# table name is changed
# old columns and new columns are not the same
As a result, when a column is added to a table, Hive also tries to update
column statistics, which is not necessary. We can loose the last condition by
checking whether all existing columns are changed or not. If not, we don't have
to update stats info.
was:
Currently when a table is altered, if any of below conditions is false, HMS
would try to update column statistics for the table:
# database name is changed
# table name is changed
# old columns and new columns are not the same
As a result, when a column is added to a table, Hive also tries to update
column statistics, which is not necessary. We can loose the last condition by
checking whether all existing columns are changed or not. If not, we don't have
to update stats info.
> Optimize the column stats update logic in table alteration
> ----------------------------------------------------------
>
> Key: HIVE-15530
> URL: https://issues.apache.org/jira/browse/HIVE-15530
> Project: Hive
> Issue Type: Bug
> Components: Hive
> Reporter: Yibing Shi
>
> Currently when a table is altered, if any of below conditions is true, HMS
> would try to update column statistics for the table:
> # database name is changed
> # table name is changed
> # old columns and new columns are not the same
> As a result, when a column is added to a table, Hive also tries to update
> column statistics, which is not necessary. We can loose the last condition by
> checking whether all existing columns are changed or not. If not, we don't
> have to update stats info.
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